So what does C-z do now that is no longer does minimize? I used it as an alias for C-x5 using: (global-set-key "\C-z" ctl-x-5-map) and now had to figure out to change it to this: (define-key osx-key-mode-map '[(control z)] ctl-x-5-map) I'd like to understand what improvement I'm giving up for this customization.